extern "C"
{
#include <libavdevice/avdevice.h>
#include <libavformat/avformat.h>
#include <libavutil/mem.h>
#include <libavutil/timestamp.h>
#include <libavutil/error.h>
}
const char *av_err2str_custom(int errnum)
{
    static char errbuf[AV_ERROR_MAX_STRING_SIZE];
    return av_make_error_string(errbuf, AV_ERROR_MAX_STRING_SIZE, errnum);
}

static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag)
{
    AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;

    // printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
    //        tag,
    //        av_ts2str(pkt->pts),
    //        av_ts2timestr(pkt->pts, time_base),
    //        av_ts2str(pkt->dts),
    //        av_ts2timestr(pkt->dts, time_base),
    //        av_ts2str(pkt->duration),
    //        av_ts2timestr(pkt->duration, time_base),
    //        pkt->stream_index);
}

void find_device(AVFormatContext **fmt_ctx, const char *device_name, AVDictionary *options = NULL)
{
    const AVInputFormat *input_fmt = input_fmt = av_find_input_format("dshow");
    if (!input_fmt)
    {
        fprintf(stderr, "dshow input format not found\n");
        return;
    }
    // 打开输入设备
    if (avformat_open_input(fmt_ctx, device_name, input_fmt, &options) < 0)
    {
        fprintf(stderr, "Failed to open dshow device: %s\n", device_name);
        return;
    }
    // 获取设备流信息
    if (avformat_find_stream_info(*fmt_ctx, NULL) < 0)
    {
        fprintf(stderr, "Failed to get stream info\n");
        return;
    }
    // 打印设备流信息
    av_dump_format(*fmt_ctx, 0, device_name, 0);
}

int main(int argc, char **argv)
{
    const AVOutputFormat *ofmt     = NULL;
    AVFormatContext      *ifmt_ctx = NULL, *ofmt_ctx = NULL;
    AVPacket             *pkt = NULL;
    const char           *in_filename, *out_filename;
    int                   ret, i;
    int                   stream_index        = 0;
    int                  *stream_mapping      = NULL;
    int                   stream_mapping_size = 0;
    int                   frame_count         = 0;

    avdevice_register_all();

    // in_filename = "mux.mp4";
    out_filename = "capture.mp4";

    pkt = av_packet_alloc();
    if (!pkt)
    {
        fprintf(stderr, "Could not allocate AVPacket\n");
        return 1;
    }

    // if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0)
    // {
    //     fprintf(stderr, "Could not open input file '%s'", in_filename);
    //     goto end;
    // }

    // if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0)
    // {
    //     fprintf(stderr, "Failed to retrieve input stream information");
    //     goto end;
    // }
    AVDictionary *options = NULL;
    av_dict_set(&options, "video_size", "640x480", 0);  // 你可以选择摄像头支持的尺寸
    av_dict_set(&options, "framerate", "30", 0);        // 摄像头支持的帧率
    // av_dict_set(&options, "pixel_format", "yuy2", 0);   // 强制使用 yuy2 替代 mjpeg
    av_dict_set(&options, "rtbufsize", "100M", 0);  // 防止缓冲区过满丢帧
    find_device(&ifmt_ctx, "video=HD Webcam", options);

    // av_dump_format(ifmt_ctx, 0, in_filename, 0);

    avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
    if (!ofmt_ctx)
    {
        fprintf(stderr, "Could not create output context\n");
        ret = AVERROR_UNKNOWN;
        goto end;
    }

    stream_mapping_size = ifmt_ctx->nb_streams;
    stream_mapping      = (int *)av_calloc(stream_mapping_size, sizeof(*stream_mapping));
    if (!stream_mapping)
    {
        ret = AVERROR(ENOMEM);
        goto end;
    }

    ofmt = ofmt_ctx->oformat;

    for (i = 0; i < ifmt_ctx->nb_streams; i++)
    {
        AVStream          *out_stream;
        AVStream          *in_stream   = ifmt_ctx->streams[i];
        AVCodecParameters *in_codecpar = in_stream->codecpar;

        if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO && in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
            in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE)
        {
            stream_mapping[i] = -1;
            continue;
        }

        stream_mapping[i] = stream_index++;

        out_stream = avformat_new_stream(ofmt_ctx, NULL);
        if (!out_stream)
        {
            fprintf(stderr, "Failed allocating output stream\n");
            ret = AVERROR_UNKNOWN;
            goto end;
        }

        ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
        if (ret < 0)
        {
            fprintf(stderr, "Failed to copy codec parameters\n");
            goto end;
        }
        out_stream->codecpar->codec_tag = 0;
    }
    av_dump_format(ofmt_ctx, 0, out_filename, 1);

    if (!(ofmt->flags & AVFMT_NOFILE))
    {
        ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
        if (ret < 0)
        {
            fprintf(stderr, "Could not open output file '%s'", out_filename);
            goto end;
        }
    }

    ret = avformat_write_header(ofmt_ctx, NULL);
    if (ret < 0)
    {
        fprintf(stderr, "Error occurred when opening output file\n");
        goto end;
    }

    while (frame_count++ < 150)
    {
        AVStream *in_stream, *out_stream;

        ret = av_read_frame(ifmt_ctx, pkt);
        if (ret < 0)
            break;

        in_stream = ifmt_ctx->streams[pkt->stream_index];
        if (pkt->stream_index >= stream_mapping_size || stream_mapping[pkt->stream_index] < 0)
        {
            av_packet_unref(pkt);
            continue;
        }

        pkt->stream_index = stream_mapping[pkt->stream_index];
        out_stream        = ofmt_ctx->streams[pkt->stream_index];
        log_packet(ifmt_ctx, pkt, "in");

        /* copy packet */
        av_packet_rescale_ts(pkt, in_stream->time_base, out_stream->time_base);
        pkt->pos = -1;
        log_packet(ofmt_ctx, pkt, "out");

        ret = av_interleaved_write_frame(ofmt_ctx, pkt);
        /* pkt is now blank (av_interleaved_write_frame() takes ownership of
         * its contents and resets pkt), so that no unreferencing is necessary.
         * This would be different if one used av_write_frame(). */
        if (ret < 0)
        {
            fprintf(stderr, "Error muxing packet\n");
            break;
        }
    }

    av_write_trailer(ofmt_ctx);
end:
    av_packet_free(&pkt);

    avformat_close_input(&ifmt_ctx);

    /* close output */
    if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
        avio_closep(&ofmt_ctx->pb);
    avformat_free_context(ofmt_ctx);

    av_freep(&stream_mapping);

    if (ret < 0 && ret != AVERROR_EOF)
    {
        fprintf(stderr, "Error occurred: %s\n", av_err2str_custom(ret));
        return 1;
    }

    return 0;
}
